Birdsall talks of about The Penderwicks and the story behind her writing:
- ''I have a theory," said Birdsall, 54, during an interview in her home near the city center, ''that the book is a memoir of my childhood -- not my actual childhood, but of the books I read over and over. Those books were my secret life. They're all part of my life memories, as though I had lived them, rather than reading them."
Birdsall's literary heroes include Louisa May Alcott, E. Nesbitt, and Edward Eager.